[ClusterLabs] Multiple nfsserver resource groups

[Strahil Nikolov]

On March 6, 2020 7:56:00 PM GMT+02:00, Christoforos Christoforou <christoforos at globalreach.com> wrote:
>Hello,
>
> 
>
>We have a PCS cluster running on 2 CentOS 7 nodes, exposing 2 NFSv3
>volumes
>which are then mounted to multiple servers (around 8).
>
>We want to have 2 more sets of additional shared NFS volumes, for a
>total of
>6.
>
> 
>
>I have successfully configured 3 resource groups, with each group
>having the
>following resources:
>
>*	1x ocf_heartbeat_IPaddr2 resource for the Virtual IP that exposes
>the NFS share assigned to its own NIC.
>*	3x ocf_heartbeat_Filesystem resources (1 is for the
>nfs_shared_infodir and the other 2 are the ones exposed via the NFS
>server)
>*	1x ocf_heartbeat_nfsserver resource that uses the aforementioned
>nfs_shared_infodir.
>*	2x ocf_heartbeat_exportfs resources that expose the other 2
>filesystems as NFS shares.
>*	1x ocf_heartbeat_nfsnotify resource that has the Virtual IP set as
>its own source_host.
>
> 
>
>All 9 filesystem volumes are mounted via iSCSI to the PCS nodes in
>/dev/mapper/mpathX
>
>So the structure is like so:
>
>Resource group 1:
>
>*	/dev/mapper/mpatha - shared volume 1
>*	/dev/mapper/mpathb - shared volume 2
>*	/dev/mapper/mpathc - nfs_shared_infodir for resource group 1
>
>Resource group 2:
>
>*	/dev/mapper/mpathd - shared volume 3
>*	/dev/mapper/mpathe - shared volume 4
>*	/dev/mapper/mpathf - nfs_shared_infodir for resource group 2
>
>Resource group 3:
>
>*	/dev/mapper/mpathg - shared volume 5
>*	/dev/mapper/mpathh - shared volume 6
>*	/dev/mapper/mpathi - nfs_shared_infodir for resource group 3
>
> 
>
>My concern is that when I run a df command on the active node, the last
>ocf_heartbeat_nfsserver volume (/dev/mapper/mpathi) mounted to
>/var/lib/nfs.
>I understand that I cannot change this, but I can change the location
>of the
>rpc_pipefs folder.
>
> 
>
>I have had this setup running with 2 resource groups in our development
>environment, and have not noticed any issues, but since we're planning
>to
>move to production and add a 3rd resource group, I want to make sure
>that
>this setup will not cause any issues. I am by no means an expert on
>NFS, so
>some insight is appreciated.
>
> 
>
>If this kind of setup is not supported or recommended, I have 2
>alternate
>plans in mind:
>
>1.	Have all resources in the same resource group, in a setup that will
>look like this:
>
>a.	1x ocf_heartbeat_IPaddr2 resource for the Virtual IP that exposes
>the NFS share.
>b.	7x ocf_heartbeat_Filesystem resources (1 is for the
>nfs_shared_infodir and 6 exposed via the NFS server)
>c.	1x ocf_heartbeat_nfsserver resource that uses the aforementioned
>nfs_shared_infodir.
>d.	6x ocf_heartbeat_exportfs resources that expose the other 6
>filesystems as NFS shares. Use the clientspec option to restrict to IPs
>and
>prevent unwanted mounts.
>e.	1x ocf_heartbeat_nfsnotify resource that has the Virtual IP set as
>its own source_host.
>
>2.	Setup 2 more clusters to accommodate our needs
>
> 
>
>I really want to avoid #2, due to the fact that it will be overkill for
>our
>case.
>
>Thanks
>
> 
>
>Christoforos Christoforou
>
>Senior Systems Administrator
>
>Global Reach Internet Productions
>
> <http://www.twitter.com/globalreach> Twitter |
><http://www.facebook.com/globalreach> Facebook |
><https://www.linkedin.com/company/global-reach-internet-productions>
>LinkedIn
>
>p (515) 996-0996 |  <http://www.globalreach.com/> globalreach.com
>
> 

I don't get it.
Why the last nfs_shared_infodir  will be mounted  on /var/lib/nfs  ?
As  far as I remember, you set that dir in any location you want as a Filesystem resource.

Note: You do realize  that mpathi on 1 host can be turned into mpathZ on the other. Either use alias for each wwid, or do not use  friendly names  on those cluster nodes.
Also, I would use LVM resource with 'exclusive=true' in order to avoid accidental activation of the LV on the other node.

Best Regards,
Strahil Nikolov